Do we just not yet understand addiction enough to treat it properly? Are we able to treat addiction (so, for example, someone could successfully limit themselves to low levels of social drinking that don't cause them harm), but doing so is so difficult and hit-or-miss, that we give up and only promote full abstinence as the solution?
I also wonder if abstaining from alcohol can have negative affects on life for some people. Some people use alcohol as a social lubricant; abstaining might mean (detrimentally) less social interaction. In some cultures/environments, not drinking can be career-limiting (I think this is toxic, but fixing that can take generations). I think it's fair to say that, on balance, the pros of not drinking to excess all the time will (nearly?) always outweigh any cons of abstinence, but can we do better than either extreme?
I poked around at some studies, and what I found was interesting. It does seem that 12-step programs tend to outperform things like cognitive behavioral therapy (though there is some disagreement here). But also many of these studies are about whether or not a given treatment achieves abstinence from alcohol, not if it treats the underlying disorder. So I'm not sure what conclusions (if any) can be drawn.
(Ultimately, though, if the 12-step program worked for you, and you're happy with the results and with your life now, that's all that matters! I don't mean to demean what you've accomplished or throw shade on the life you have now. I just think this is a very high-profile societal/health issue that we seem to deal with in a very different way than we deal with others, and that seems strange to me.)